Dimerization of olefins with chromium halide complex catalysts systems

ABSTRACT

Olefins are dimerized by contacting the olefin with a homogeneous catalyst comprising a chromium halide complex in combination with an ethylaluminum dichloride adjuvant. Additionally, a heterogeneous catalyst is prepared by depositing upon a suitable support the homogeneous combination mentioned above and contacting the olefin to produce dimers thereof.

Unite States i Zuech 5] Apr. 10, 1973 DRIZATION OF OLES WITH [56]References Cited CHRONHUM HAL 5| COWLEX a 3 3 3 .6 .W 3 CATALYSTSSYSTEMS UNIED STATES PATENTS 75 Inventor: Ernest A Zuech Bartlesville,Okla 3,081,287 3/1963 COOVer et a1. ..260/93.7 3 H 3 3,008,943 11/1961Guyer ..260/93.7 1 Asslgnee= Phllllps Petroleum p y 3,318,860 5/1967Eichenbaum... ..260/93.7 Bartlesvllle, Okla- 3,379,706 4/1968 Wilke..260/683.l5 x

1221 Filed 219, 1971 Primary Examiner-Paul M. Coughlan, Jr. [21] Appl.No.: 129,226 Attomey-Young and Quigg Related US. Application Data 57ABSTRACT [60] 52E97 1 1 1968 Olefins are dimerized by contacting theolefin with a 6 3 12 i gg gg iggzx'ggg 2; homogeneous catalystcomprising a chromium halide 635;700,May 3 abmidoned complex incombination with an ethylaluminum p 7 V W dichloride adjuvant.Additionally, a heterogeneous [52] Us. CL I 260/683 15 D 260/666 Acatalyst is prepared by depositing upon a suitable sup- [51] Int Cl (30%3/10 port the homogeneous combination mentioned above [58] andcontacting the olefin to produce dimers thereof.

Field of Search ..260/683.l5 D, 666 A 11 Claims, No DrawingsDIMERIZATION F OLEFINS WITI-l CHROMIUM I-IALIDE COMPLEX CATALYSTSSYSTEMS This application is a divisional of application Ser. No.778,307, filed Nov. 22, 1968, now US. Pat. No. 3,627,700 which is acontinuation-in-part of copending applications Ser. No. 635,649, filedMay 3, 1967, now abandoned, and Ser. No. 635,700, filed May 3, 1967, nowabandoned.

FIELD OF THE INVENTION This invention relates to the conversion ofolefin hydrocarbons and a homogeneous catalyst for such conversion. Inanother aspect, this invention relates to DESCRIPTION OF THE PRIOR ART Anumber of systems have been recorded in the prior art in which certaintransition metal salts or complexes have been found to be useful informing catalysts for the dimerization and oligomerization of olefins.In particular, a great number of nickel complexes have been found usefulfor this purpose, particularly when used with an organoaluminumadjuvant. It has now been found, however, that certain chromiumcomplexes can be used to form catalyst systems having high activity andselectivity for olefin dimerization.

OBJECTS OF THE INVENTION It is an object of this invention to provide amethod and a catalyst for the conversion of olefin hydrocarbons todimers thereof. It is also an object of this invention to provide ahomogeneous catalyst for dimerizing olefins. It is still another objectof the invention to provide a heterogeneous catalyst for dimerizingolefins. Other aspects, objects and advantages of the invention will beapparent to one skilled in the art upon reading the summary of theinvention, the description of the preferred embodiments, and the'claims.

SUMMARY OF THE INVENTION The method of the invention comprisescontacting acyclic or cyclic olefins, or mixtures thereof, with acatalyst system resulting from the admixture of (a) a chromium halidecomplex represented by the formula l)2( )2 2: m z. z)a a, a)2 CrX,]wherein X is chlorine, bromine, iodine, or fluorine and (L,), (L and (Lare selected pyridine, pyridine oxide, phosphine, or phosphine oxideligands, and the total number of carbon atoms in the chromium halidecomplex does not exceed about 50, and (b) ethylaluminum dichloride(EADC), to produce dimers of the olefins which are contacted with thecatalyst. The invention also contemplates the catalysts which are formedfrom admixture of the chromium halide complexes and ethylaluminumdichloride in either a homogeneous or heterogeneous system. When theheterogeneous system is employed, the catalyst system compriss thechromium halide complex-EADC which is deposited upon a suitable support.

The (L,) ligands which are applicable in the chromium halide complexesof the catalyst system of the present invention are selected from:

0 N III R'-PR R-i-R Ru or R1:

The (L ligands which are applicable are represented by:

The (L ligands which are applicable are represented by:

flf ij Pd RI wherein R is an aromatic or saturated aliphatic hydrocarbonradical having up to 20 carbon atoms, R is a saturated aliphatichydrocarbon radical having up to 20 carbon atoms, and n is a wholenumber from 0 to 4, inclusive, and wherein the total number of carbonatoms in the chromium complex does not exceed about 50.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of chromium complexesof the type (L,) (NO) C1'X are:

bis(tributylphosphine)dinitrosyldichlorochromium bis(tricyclopentylphosphine )dinitrosyldiiodochromiurn bis(triphenylphosphine oxide)dinitrosyldichlorochromium bis(tributylphosphine oxide )dinitrosyldichlorochromium bis(tricyclopentylphosphine oxide )dinitrosyldibromochromium bis(tribenzylphosphine oxide )dinitrosyldiiodochromium bis(tri-o-tolylphosphine oxide )dinitrosyldifluorochromium bis(pyridine)dinitrosyldichlorochromium bis(4-methylpyridine)dinitrosyldibromochromiumbis(2-methyl-4-isobutylpyridine)dinitrosyldiiodoch romiumbis(4-phenylpyridine )dinitrosyldifluorochromium bis(4-eicosylpyridine)dinitrosyldichlorochromium bis(pyridine oxide)dinitrosyldichlorochromium bis(4-cyclohexylpyridineoxide)dinitrosyldibromochromium bis(2,3-dimethyl-4,5-diethylpyridine ide)dinitrosyldiiodochromium and the like and mixtures thereof.

Examples of chromium complexes of the type (LQ CrX are:

bis(tributylphosphine)dichlorochromiumbis(tridecylphosphine)dibromochromium bis(triphenylphosphineoxide)dichlorochromium bis(4-ethylpyridine)dichlorochromiumbis(tridecylphosphine oxide)dibromochromium bis(triethylphosphineoxide)diiodochromium bis(tribenzylphosphine oxide)difluorochromiumbis(pyridine)dichlorochromium bis(3,5-dimethylpyridine)dichlorochromiumbis(4-phenylpyridine)dibromochromium bis(4-clodecylpyridineoxide)dibromochromium bis(3-methy]-4-cyclohexylpyridineide)difluorochromium and the like and mixtures thereof.

Examples of (L CrX chromium complexes are:

tris(pyridine)trichlorochromium tris(4-ethylpyridine)trichlorochromiumtris(pyridine)tribromochromiumtris(2,3,4-trimethylpyridine)triiodochromiumtris(4-eicosylpyridine)trifluorochromiumtris(4-benzyl-5-methylpyridine)trichlorochromiumtris(3-cycloheptylpyridine)trichlorochromiumtris(4o-tolylpyridine)tribromochromiumtris(3-isobutylpyridine)trichlorochromium and the like and mixturesthereof.

Examples of [(L Cr X chromium complexes are:

[bis(tributylphosphine)trichlorochromium][bis(trimethylphosphine)triiodochromium]Ibis(tricyclohexylphosphine)tribromochromium1[bis(trieicosylphosphine)trichlorochromiuml[bis(tridecylphosphine)trichlorochromium] [bis(tricyclobutylphosphine)trifluorochromium [bis(tri-sec-butylphosphine)trichlorochromium] andthe like and mixtures thereof.

Among the olefins which are dimerized according to the present processare acyclic and cyclic monoolefins having up to about 12 carbon atomsper molecule, and mixtures thereof. The acyclic monoolefin can containterminal or internal unsaturation, and be branched or unbranched. Thelower acyclic terminal olefins are generally preferred and the processof the invention is particularly effective for the dimerization ofethylene and propylene, and the co-dimerization of ethylene andpropylene.

The chromium halide complexes described above can be prepared by anysuitable method. For example, the chromium halide complex can be formedby contacting a chromium halide, such as CrCl with an applicablephosphine, phosphine oxide, pyridine, pyridine oxide, nitric oxide, or anitrosyl halide corresponding to the ligands described above underconditions of time and temperature which are sufficient to permit thecomplex to be formed. In such a preparation, the molar proportion of thechromium halide salt to the coordinating compounds will correspond,approximately, to the stoichiometry indicated in the formulas of thechromium complexes listed above. Nitric oxide, however, can be, andgenerally is, present in substantial excess. These ingredients aregenerally mixed at a temperature in the range of from about to about 130C, preferably to about 60 C, for a time in the range of from a fewseconds up to about 24 hours, preferably in the presence of a diluent inwhich the components of the reaction are at least partially soluble. Anyconvenient diluent such as methylene chloride, benzene, chlorobenzene,and the like, can be used for this purpose.

The chromium halide complex of the catalyst system is prepared beforecontact is made with the ethylaluminum dichloride. It is sometimesdesirable to remove excess or unreacted NO or nitrosyl halides from thechromium halide complex, if they are present, before contact is madewith the aluminum component. Such removal can be conveniently carriedout by warming the complex under reduced pressure to evaporate the NO ornitrosyl halide. Such removal of this excess reagent is not a necessitybut is frequently desirable, because the excess reagent appears toconsume some of the aluminum component which is added later. For thissame reason, grossly excessive amounts of any of the complexing agentsshould be avoided.

The chromium halide complex and aluminum components of the catalystinvention are generally combined, to prepare the active catalyst, inproportions in the range of from about 0.1 :1 to about 20:1, preferablyfrom about 1:1 to about 10:1, moles of the aluminum component to molesof the chromium component. The catalyst is prepared simply by combiningthese components under conditions of time and temperature which permitthe catalytically active catalyst to be formed. This combination occursvery readily, and, in general, the components can be mixed at anyconvenient temperature within the range of to about C for a few secondsor for periods up to several hours in the presence of a diluent in whichboth the components are at least partially soluble. Any con venientdiluent such as chlorobenzene, methylene chloride, ethylene chloride,benzene, xylene, toluene, cyclohexane, and the like can be used for thispurpose. Halogenated diluents are generally preferred. The mixing ofthese two catalyst components is generally carried out in thesubstantial absence of air or moisture, generally in an inertatmosphere. After the catalytic mixture is formed, it need not beisolated but can be added directly to the reaction zone as a solution initspresence of a diluent such as that used for the catalyst preparationif desired. The time of contact of the olefin with the catalyst for thedimerization of the olefin will vary depending upon the desired degreeof conversion, but generally will be in the range of from about 0.1minute to about 20 hours, preferably 5 to minutes. The proportion ofcatalyst composition to olefin feed in the reaction zone will generallybe within the range of from about 0.001 to about 0.1 mole of chromiumcomplex per mole of olefin feed.

Any suitable contacting technique can be utilized for the olefindimerization and batchwise or continuous operation can be utilized.After the desired degree of conversion of the olefin to the dimer, theproducts so formed can be separated and isolated by conventional meanssuch as by fractionation, crystallization, adsorption, and the like. Theunconverted feed material can cracked by conventional methods to makeisoprene. Propylene dimers, as well as dimers of other olefins, can beemployed as feedstock for the oxo-process to make oxo alcohols which areused in the preparation of be recycled through the reaction zone. Ifdesired, the 5 plasticizers. The present dimerization process can alsocatalyst can be deactivated by treatment with suitable be used veryeffectively in conjunction with olefin disdeactivating agents such aswater or alcohol, prior to ro orti tion processes. For example, when theep r Ofthe products propylene is disproportionated to produce ethyleneThe homogeneous catalysts of this invention can be d butenes, h can b ii d to produce ddeposited upon a suitable support or carrier and used inditional butenes. the dimerization reaction. Preferably, but not limitedit is understood that the foregoing discussion of the to, the olefinfeed is in the vapor phase when contacted readtion of the suitableolefin feed material with the with the heterogeneous catalyst. Catalystsupports incatalyst is not limited to the preparation of dimers, cludesolid, inorganic or organic materials convenalthough the reactionproduct produced under the contionally used as catalyst supports orcarriers such as silditions as discussed previously contains substantialica, alumina, silica-alumina, titania, boria, zeolites, ion amounts ofolefin dimers. The reaction product also exchange resins, solid polymerscontaining functional comprises other oligomers of theolefin feedmaterial. groups such as those prepared by the polymerization of By igomr it is meant e trlmel's, tetl'amefs, and the 4-vinylpyridine,vinyldimethylphosphine, and the like. ll 0f th l fin f d materlal.

The support can be impreganted with the homogeneous catalyst by wettingthe support with a solution of EXAMPLES the catalyst in a solvent whichis then evaporated. The A number of l fi dimerization runs were carriedSupport can also be impregnated with either the out using severaldifferent catalyst systems. The conchromium or aluminum component andthe remaining versions were carried out batchwise in a 300 mlaucomponent can be added later. For example, the Solid toclave. Thecatalyst preparation procedure was as folsupport material can be impr gnwith h h lows. A stoppered bottle was dried and flushed with umcomponent and the resulting composite nitrogen. The chromium complex wasadded first folveniently t r d until required- JllSt Prior to the lowedby 100 to 150 ml of chlorobenzene diluent and composite can be treatedwith the aluminum comthen the ethylaluminum dichloride was added. Thisponent, or, if the reaction is in the liquid phase, the alusolution wasthen transferred to the autoclave which minum component can simply beadded to the reaction was similarly dried and flushed with nitrogen. Thefeed zone. Among solvents suitable are relatively low-boilol fi wa thenadmitted to the autoclave at the ing organic solvents such as pentane,methylene 3S prescribed pressure. Table I gives the data and thechloride, cyclohexane, and the like. The amount of results of the runsutilizing different catalyst systems homogeneous catalyst added to thesupport will be and different conditions.

TABLE I Selec- Milli- EADO, Temp., P, Time, Dlmers, tivity, Feed Crcomplex moles ml. C. p.s.i.g. hr. g. percent 02- (Py);CrOl3 0. 1 0. 5 17750 1 20. 5 s2 Cz" (PyhCrCla 0. 1 0. 5 50 750 1 50. 7 s3 02- (P30301101:0. 1 0. 5 75 500 1 as 00 G2- I! PyhCrCla 0.1 0. 5 50 500 1 t Cz- [(B'l1P)zCIC13]2 O. 1 O. 5 50 500 1 51 83 c2- (4-EtPy)aCrCl5 0. 1 0. 5 50 5001 s0 02- (4-EtPyhOr0ll 0. 05 0. 25 500 1 53 81 Cz (4-EtPy)aCr C13 0. 0250.125 50 500 1 59 85 c2- (4-EtPyhOrCh 0. 05 0. 5 50 500 1 55 78 c2-(4-EtPy)z(NO)zCrCl2 0. 05 0. 5 50 500 1 59 Cr (Ph PO)(NO)zCrGl2 0. 05 0.5 50 500 1 57 s2 03- (Py)aCrCl; 0.1 0.5 50 1.5 17.3 -58 Or (4-EtPy)aCrCl0. 05 0.25 50 1.5 42 -57 Cf/Ca' (4-EtPyhCrCl; 0.05 0.5 50 500 2 1Hydrogenation of the hexenes yielded 31% n-hexane, 69% Z-methylpentane,and a trace 0! 3-methylpentanc.

2 59 g. O present at beginning of run.

3 22.6 g. Crs, 10.4 g. Crs, 6.9 g. Crs, 1.5 g. Crs, 0.8 g. Crs, 1.0higher.

4 Further analysis of the pentcnes showed 65.8% t-Z-pentene, 23.4%c-Z-penteno, 5.4% 3-methyl-l-butcne 4.8% l-pentene, 0.6%2-methyl-2-butene, and traces of 2-methyl-1-hntem-,.

5 Used MASC in place of EADC.

Other methods of contacting the olefin with the catalyst of theinvention will be within the knowledge of those skilled in the art.Accordingly, the disclosure of the invention wherein acyclic or cyclicolefins are dimerized by contacting with a catalyst formed on admixtureof (a) (L,) (NO) CrX (L,) CrX (L CrX or [(L CrX wherein X is chlorine,bromine, or iodine, and (L (L and (L are selected pyridine, pyridineoxide, phosphine or phosphine oxide ligands, and the total number ofcarbon atoms in the chromium halide complex does not exceed about 50,and (b) ethylaluminum dichloride in a homogeneous system or bycontacting the olefin in the presence of a catalyst formed on admixtureof (a) and (b) which has been deposited upon a suitable support toprovide a the (L ligands are represented by the formula wherein R is anaromatic or saturated aliphatic hydrocarbon radical having up to 20carbon atoms, R is a saturated aliphatic hydrocarbon radical having upto 20 carbon atoms, n is a whole number from O to 4, inclusive, and thetotal number of carbon atoms in the chromium halide complex does notexceed about 50, and (b) ethylaluminum dichloride.

2. A method according to claim 1 wherein the chromium halide complex is(L,) (NO CrX 3. A method according to claim 2 wherein the (a) componentof the catalyst is bis(triphenylphosphineoxide)dinitrosyldichlorochromium or bis(4-ethylpyridine)dinitrosyldichlorochromium.

4. A method according to claim 1 wherein the chromium halide complex is(L CrX 5. A method according to claim 4 wherein the (a) component of thecatalyst is tris(pyridine)trichlorochromium ortris(4-ethylpyridine)trichlorochromium.

6. The method of claim 1 wherein the olefin is contacted with thecatalyst at a temperature of 10 to C.

7. The method according to claim 1 wherein the catalyst is depositedupon a suitable support.

8. A method according to claim 1 wherein the olefin is ethylene,propylene, or a mixture of ethylene and propylene.

9. A method of producing a reaction product which comprises olefindimers, the method comprising reacting olefins selected from acyclicmonoolefins and cyclic monoolefins, having from two to about 12 carbonatoms or mixtures thereof with a catalyst comprising (a) a chromiumhalide complex represented by the formula (L (;rX wherein X is chlorinebromine, iodine or fluorine, and (L is represented by the formulas ,7 vt t O t t N T g a Ri-R R or R wherein R is an aromatic or saturatedaliphatic hydrocarbon radical having up to 20 carbon atoms, n is a wholenumber from 0 to 4, inclusive, and the total number of carbon atoms inthe chromium halide complex does not exceed about 50, and (b)ethylaluminum dichloride.

10. A method according to claim 9 wherein the chromium halide complex is(L CrX 11. A method according to claim 9 wherein the (a) component ofthe catalyst is bis(4-ethylpyridine)dichlorochromium.

2. A method according to claim 1 wherein the chromium halide complex is(L1)2(NO)2CrX2.
 3. A method according to claim 2 wherein the (a)component of the catalyst is bis(triphenylphosphineoxide)dinitrosyldichlorochromium orbis(4-ethylpyridine)dinitrosyldichlorochromium.
 4. A method according toclaim 1 wherein the chromium halide complex is (L2)3CrX3.
 5. A methodaccording to claim 4 wherein the (a) component of the catalyst istris(pyridine)trichlorochromium ortris(4-ethylpyridine)trichlorochromium.
 6. The method of claim 1 whereinthe olefin is contacted with the catalyst at a temperature of 10* to 80*C.
 7. The method according to claim 1 wherein the catalyst is depositedupon a suitable support.
 8. A method according to claim 1 wherein theolefin is ethylene, propylene, or a mixture of ethylene and propylene.9. A method of producing a reaction product which comprises olefindimers, the method comprising reacting olefins selected from acyclicmonoolefins and cyclic monoolefins, having from two to about 12 carbonatoms or mixtures thereof with a catalyst comprising (a) a chromiumhalide complex represented by the formula (L1)2CrX2, wherein X ischlorine, bromine, iodine or fluorine, and (L1) is represented by theformulas
 10. A method according to claim 9 wherein the chromium halidecomplex is (L1)2CrX2.
 11. A method according to claim 9 wherein the (a)component of the catalyst is bis(4-ethylpyridine)dichlorochromium.